Boat construction



June 8, 1937. c. w. STIVER BOAT CONSTRUCTION I Filed May 4, 1935 0 E T M m 0 VW T m M m a Patented June 8, 1937 UNITED STATES ??ATENT OFFIQE' 6 Claims.

This invention relates to water-craft, such as canoes, small boats, pontoons for air craft and the like, and it pertains more particularly to a novel hull or framework construction.

The objects of the invention are to provide an article of that class possessing unusual lightness combined with great strength and durability; of simple construction capable of being produced in quantities with a minimum of labor; of neat and attractive shape and appearance; unusually and inherently buoyant in case of submergence; safe against accidents such as striking submerged rocks when running rapids, and easily portable.

The foregoing objects and others that will appear later in the specifications are attained. by

the following improved and novel features: individual hollow tubular buoyant ribs that constitute integral elements of the framework or skeleton of the hull and present extensive bearing surfaces for supporting the hull sheathing; including a novel method of making such ribs; individually buoyant rub strake members for the gunwales; a novel means for assembly and securing together the ribs and gunwale-s.

Primarily the claimed invention is found in the idea of utilizing each tubular rib, and, if desired, each gunwale, as an individual water-tight buoyant unit which is sealed at its ends to constitute an impervious air chamber, and also in.- cludes the idea of making the buoyant ribs of light magnesium-aluminum alloy metal so as to produce a craft that is inherently unsinkable.

A structure in which the invention is embodied is shown and described herein, a canoe being chosen for purposes of illustration.

' In the accompanying drawing like parts in the several views are designated by like characters of reference.

Fig. 1 is a perspective View of a canoe constructed according to my invention, as it appears when viewed from above, the floor boards being removed.

Fig. 2 is a view in elevation of an amidship rib as seen from forward or aft, including end views of the rib. t

Fig.3 is a fragmentary sectional view of a rib with flexible forming strips in place, the position of the rib and strips before bending being indicated by broken lines.

Fig. 4 is a plan view of a U-shaped rib with the flexible forming strips therein indicated by dotted lines.

I Fig. 5 is a plan View of the rib shown in Fig. 4

as it appears after the bottom portion of the 55 rib has been offset laterally so as to conform the upright ends of the rib to the lengthwise taper and faired shape of the hull.

Figs. 6 and '7 are enlarged sectional details taken on line 66 of Fig. 1, showing two suitable constructions of the gunwale and rib assembly.

Fig. 8 is a plan View of a portion of a gunwale, constructed according to Figs. 6 or '7.

Figs. 9 and 10 are fragmentary vertical transverse sectional views of the bottom part of the hull with diagrammatic end details showing two appropriate forms of keel structures and also showing ribs of alternative cross-sectional shapes.

Fig. 11 is a diagrammatic view showing the pattern of hull sheathing, made of a single sheet of metal, or of two or four sheets.

The following elements constitute the framework of a canoe made according to my invention: Open gunwales, each of which comprises an inboard reinforcing strip lyan outboard hollow 'rub strake 2 having sealed ends 3; a keel 4 or 4a (if the use of the craft renders a keel desirable) flat-faced tubular ribs 5; fasteners 6, 6:1, by which the rib-s are secured water tight to the gunwales, as in Figs. 6, 7, 8, and to the keel, as in Figs. 9, 10; and sheet metal sheathing, which is sustained and supported by the tubular ribs.

The frame structure herein disclosed diifers' in important respects from earlier known structures wherein round iron or steel tubes constituted the transverse ribs, and wherein round tubes 0 were used as supports for deck coamings, and still others for longitudinal hull reinforcements. The present improvement distinguishes also from earlier structures wherein tubes were employed as buoyant elements but did not constitute strengthening members for the hull.

The gunwales, ribs and keel, as has been noted, are preferably made of magnesium-aluminum a1- loy, which is very light, having a specific gravity of less than 2.0. For canoe ribs, tubing one and seven-eighths inch diameter with a onesixteenth inch wall, flattened, is very satisfactory.

The novel shape and structure of the ribs and gunwales made as herein described, and'their mode of assembly, is advantageous in that there is imparted to the framework such a degree of strength and supporting value that, notwithstanding its extreme light weight, it is unnecessary to secure the sheet metal sheathing to the ribs except at points along the gunwales and along the keel.- It may be explained here that a sheet metal sheathing, preferably made of the alloy referred to, can be formed conveniently from either one, two, or four sheets cut to the shapes indicated at a, b, c, d, Fig. 11. Whether the entire pattern of Fig. 11 is used, or only the two upperv and lower halves, or all four quarters are used,

. depends upon the size of the hull and the facilities available to the builder for handling and shaping various size sheets by the preferred methd, which is bumping by means of a power hamas dents or bulges at points .of fastening that 7 would detract from the smooth, clean out workmanlike appearance of the craft. Labor cost also is thereby reduced.

The gunwale assembly,-shown in Figs. 1, 6, 7, 8, comprises a strip I of reinforcing material that extends fore and aft and overlies the inboard faces 5a of the upper ends of the ribs 5; and

v a hollow water-tight rub strake 2, parallel with the reinforcing strip I, applied to the flat outboard faces 5b of the rib ends. A stay-bar 6, passing through the strip l, rib 5 and rub strake 6, secures the assembly. The ends of the staybar 6 are riveted, as shown, or welded. The rivet members 5, also the keel rivets 6a, are preferably passed through rubber plug members 3, 3a in the tube 5 to make the saidmembers water tight.

The above described novel gunwale structure has advantageous features. It possesses great strength to resist athwart-ship stresses, for example, any tendency to buckle the gunwales when the boat or canoe is turned on its side, ashore, to empty water from it. The 'gunwale possesses inherent buoyancy in event of submergence, sincev thehollow rubstrakes 2, which are plugged or sealed, as by rubber plugs 3 in their ends, constitute individual air chambers. This gunwale structure can be easily and quickly assembled, as is evident upon inspectionof the drawing.

The ribs 5 also comprise impervious hollow buoyant members.

Eachrib has a fiat outboard wall 52) of sub-- stantially rectilinear cross-sectional shape.

The term flat applied to the tubular rib means primarily a rib having at least its outboard wall 5b shaped to lie fiatwise against the sheathing 1' so as to presentupon it a bearing area of large extent. It "is relatively unimportant whether the inboardwall 5a of the tube is flat,

as shown in Figs. 2, 8, 10, or is rounded, as in the alternative form, Fig. 9. The rib itself is shaped so as to conform to the cross-sectional contour ,of the hull as it bends away from the keel, if it is to be used amidships, and it likewise conforms to the fore and. aft taper of the hull if it is to be used in the bow orstern, being faired for that purpose as is indicated by the divergent broken lines in Fig. 5. I

The ends of each rib 5 are sealed water-tight by anysuitable means, although I prefer the form illustrated, namely, plugs of elastic impervious material, such as rubber.

or into the ends of the gunwales, as indicated at 3-, or both. -A metal rib made in this" manner and sealed at its ends as described provides a very 1 light but exceptionally strong element for the framework of the hull.

Ribs of this description possess the following port the sheet metalhull against forces,-such as These plugs may 7 be tightly driven'into the ends of the tubular rib,

inward pressure due to submerg'ence, water slaps, or striking snags. For example, in the actual specimen represented in Fig. 1, each rib of the size previously mentioned gives a fair bearing face one and seven-eighths inch wide upon the sheathing and so the twenty ribs give a total width of thirty seven and one half inches, equivalent to a total shell area directly supported by ribs equal to one-third of the entire area of that part of the hull which lies between the points X, X, Fig. 1. Moreover, the ribs that are indicated forward and aft of amidships are of such shape as to present extraordinary resistance against any normal tendency of the hull to give or spring when the boat is heavily loaded amidships so that its buoyancy toward the bow and stern tends to lift those parts and thereby subject the gunwales to endwise compression stresses and the keel to c tension. It will be apparent that stresses set up under such circumstances are characterized by their tendency to rotate certain of the ribs as though their bottoms werehinged to the keel. In practice that tendency is counteracted, partly by the fiat-faced shape of the tubular ribs and to a considerable degree by the strength which is imparted to the rib by a middle kink or bend in the bottom part of the rib, shown at 8 in Figs. 1 and 5; the flat bottom of the bent portion'8 provides the equivalent of an increased base, B, Fig. 5, in a direction lengthwise of the hull, and gives the hull adequate strength to resist distortion under all conditions of use.

A new and useful method or art of producing a hollow tubular rib having the above-mentioned characteristics is a feature of my claimed invention andwill now be described. Referring to Figs. 3,, 4, and 5, numerals 9 and I0 designate superimposed fiat strips of flexible material, wood for example. These strips are first lubricated by The cross-sectional shape of the conjoined or superimposed strips 9, l0 isappro-ximately that of the interior. of the tube 5. The resultant tubeand-strip assembly is then bent as by rolling, into the desired shape of a boat's rib, and finally the flexible strips 9 and H! are withdrawn by sliding them endwise. The overlying lubricated strips satisfactorily sustain the walls of the tube during the bending operation, sliding somewhat upon each other as bending progresses. They efiectu ally prevent wrinkles or creases from forming in the tube wall at the inside of the bend. One strip, as 9, can be easily pulled out, sliding upon the other, and the second readily follows. The foregoing improved method applies to ribs for, say, the midship zone of a canoe, where the two upright ends of a flat faced rib are usually parallel, as indicated in Figs. 2 and 4.

To produce faired metal'ribs wherein the outboard faces 5b of their upper ends-are required to c o r iform with the longitudinally tapered contour of the hull at. a place forward or aft of the midship zone, the strips 9, ll! are of appropri ate length to extend from the ends of the tube to about its mid-length, where their ends may be diagonally abutted as shown by. the dotted line H in Fig. 4. I p x A rib such as that now under consideration is bent or rolled into shape as above described, and. its mid-length portion near the keel ls offset by bending in a direction perpendicular to the general plane of the rib, as shown in Fig. 5, where the central vertical arrow shows the direction of application of the bending forces. The bending or kinking at 8 may be produced by a press, not shown, equipped with suitably shaped formers or dies. The amount of the offset or bend 8 should be sufiicient to deflect the outboard faces 52) of the upright portions of the rib and bring them into accurate conformity with the appropriate hull contour where the rib is to be used. Such a deflection of the rib faces 51) is indicated by the broken lines in Fig. 5.

Certain of the appended claims are directed to the novel construction of elements constituting the whole hull structure as set forth in the foregoing description, other claims for the separate parts, and still other claims for the separate sub-processes, or combinations possessing invention, novelty and utility.

As an example of such sub-combinations, it may be noted that while I have shown and described the ribs 5 as being hollow and sealed at their ends, yet the feature of the rib wherein the offset 8 is employed to produce the non-parallel ends shown in Fig. 5 is believed to be new and useful irrespective of whether the rib is hollow or is made of a solid bar, and for that reason certain of the claims are not limited to the hollow tubular rib structure.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A boat having hollow tubular water-impervious buoyant rib members, each provided with sealed ends and each constituting an isolated chamber, said rib members being made of corrosion-resistant metal of specific gravity less than 2.0 and of flat cross-sectional shape at their outboard faces, rub strakes fastened to said ribs and presenting therewith a unitary hull framework,

and a hull sheathing of sheet metal secured to the said flat faces of said ribs at points along the bottom portions thereof and at the end portions of said ribs adjacent said rub strakes.

2. A boat including a water tight tubular U- shaped rib having sealed ends, the external wall of said rib being of substantially rectilinear cross-sectional shape, the mid-length portion of said rib being bent laterally outward from the principal plane of the rib, whereby the outer faces securing together said reinforcing strip,

of upwardly projecting end portions of said rib are positioned in angularly related planes.

3. A framing element for a boat comprising a rib having its outer face substantially rectilinear in cross-sectional shape, the mid-length of said element presenting a portion projecting beyond its principal plane, said rib having end portions that project upwardly with their outer faces in planes angularly positioned relatively to each other.

4. In a boat, a gunwale structure comprising in combination, U-shaped spaced ribs located transversely of the boat, a reinforcing strip of material extending lengthwise of and overlying the inner faces of the end portions of said ribs, and a hollow tubular water-tight rub strake spaced from and parallel with said reinforcing strip and overlying the outer faces of said ribs, fasteners oneof said ribs, and the rub strake.

5. A boat including a faired hull framework having a keel member, gunwales each comprising a reinforcing strip and a rub strake member made of a single length of hollow tubing having sealed ends, hollow ribs spaced apart and having their upper ends secured between said strip and gunwale, each rib consisting of a single piece of flat tubing shaped to conform with the horizontal and transverse contour of the faired hull and sealed at its ends, to present a unitary cellular rib capable of retaining its buoyancy when entirely submerged, and fastening means securing the upper ends of said ribs to said gunwales, the middle parts of said ribs being secured to said keel member. 1

6. A boat comprising a framework including, ribs having end portions that project upwardly so as to present outer faces in planes angularly disposed relatively to each other, the midsection of said rib bent in a direction lengthwise of the boat, said framework also including a keel member and gunwale members; the bent portion of the rib being fixed to said keel to said gunwales; and a sheathing of sheet material secured to the keel and also secured along its upper marginal edges to the gunwale-s; those portions of the ribs intermediate the keel and the gunwales being unattached to said sheathing,

CHARLES W. STIVER.

member, the upwardly projecting portions of said ribs being secured 

